I don't wear a jacket that often, so I've never been in the habit of carrying in a jacket pocket. I did have an incident where I traveled up north and was wearing a jacket. I was taking a little j frame revolver out to the car with me one morning, so I just slipped it in the jacket pocket. I decided to stop for breakfast in the hotel lobby, and it was warm, so I took the jacket off. I finished my breakfast, and flopped my jacket over my arm, forgetting the revolver was in there.
The revolver slipped out as I was walking out the door, bounced off my foot as I stepped forward, and skittered 15 or 20 feet across the parking lot.
I looked around 360 degrees as discreetly as possible, and no one seemed to notice. I picked it up and continued out to my car.
I don't do that anymore.
I know people who will keep a pistol in the nightstand at a hotel. I don't do that either. I learned from someone else's mistake on that one instead of my own.